Slide valve under primary control

摘要

Springs (18,19) in primary control (6) and damping (16) chambers operate between valve housing (1) and respective pistons (3) or (4), using spring constants whose value greatly reduces or cancels out the axial disturbance caused by the pressure differential across the piston faces. For preference, these are compression springs (18,19), having identical spring constant. Primary pressure admitted to chamber (6) via the proportionating valve (9) moves the slide (5) via piston (3) so as to close off the main pressure return (15) and open the infeed (13). The related differences in the sections to be closed and opened by the slide give a pressure differential across faces (20,21) which in turn seeks to augment the movement of the slide. This is counteracted by the identical spring action (18,19).